| 摘要 |
PURPOSE:To eliminate the pressure compression of an optical fiber sufficiently by reducing the tensile strength of die drawing by utilizing the curing contraction of resin. CONSTITUTION:The optical fiber 2 is passed through a mandrel 2 and rovings 5... are dipped in resin baths 4... and drawn in a die 1 so that resin is heat set in the die 1. Then, the resin finishes being heat set at the tip 20 of the mandrel 2 and a gap (normally 0.2-0.5mm) is formed between the set resin containing fiber layer P and optical fiber 3. The setting of the resin in the die causes setting contraction to reduce the adhesive strength between the internal surface of the die and set layer, so the drawing force is reduced and drawing formation is facilitated. Further, even if the setting contraction of the resin is caused, the optical fiber is shielded by the mandrel against the setting shrinkage force during the process of the setting, so the pressure of the optical fiber is removed.
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